Composition and methods for inhibition of metal corrosion for use in the oil and gas industry

Abstract

Corrosion inhibiting compositions and methods of inhibiting corrosion on a metal surface commonly used in the petroleum industry is disclosed. The corrosion inhibitor includes at least one azole, at least one polypeptide derived from amino acid, at least one intensifier preferably from metal halides, and at least one surfactant. The methods include combining effective amounts of the corrosion inhibitor composition and contacting a metal surface in aqueous environment commonly found in oil and gas industry. The composition is very effective against corrosion of metals in contact with aqueous media when used in a dosage as low as 50 ppm.

The invention claimed is: 
     
       1. A benzimidazole composition comprising:
 0.01 to 5.00 wt % of at least one benzimidazole, 
 0.01 to 1 wt % of at least one polypeptide, 
 0.0015 to 0.01 wt % of at least one surfactant, 
 0.1 to 0.5 wt % of at least one metal halide; and 
 water; 
 wherein the at least one benzimidazole has the formula: 
 
       
         
           
           
               
               
           
         
         wherein R1 is a thiol group, amine group, a substituted amine group, methylamine, ethylamine or another amine-bearing group, carboxylate group, amide group containing an aromatic group, pyridyl group, azo group, nitrile group, methylthio group, 2-piperazino group, 2-bromophenyl group, sulfonic acid group, or a mercapto group and wherein R2 is a carboxylate group, thiol group, an aromatic carbonyl group, hydroxy group, methyl amino group, amide group, or ester group; and 
         wherein the at least one polypeptide has the formula: 
       
       
         
           
           
               
               
           
         
         wherein R4, R5 and R6 are independently hydrogen or alkyl groups; 
       
       wherein R2 is optionally an aromatic carbonyl group which comprises an alkyl benzyl carbonyl group having the general structure below and wherein R3 is C 1 -C 3  alkyl: 
       
         
           
           
               
               
           
         
       
     
     
       2. The benzimidazole composition of  claim 1 , wherein the at least one benzimidazole is substituted with at least one thiol group or at least one carboxylate group. 
     
     
       3. The benzimidazole composition of  claim 1 , wherein the at least one surfactant is a quaternary ammonium surfactant. 
     
     
       4. The benzimidazole composition of  claim 1 , wherein the at least one surfactant is cetyl trimethyl ammonium bromide. 
     
     
       5. The benzimidazole composition of  claim 1 , wherein the at least one surfactant is a polysorbate. 
     
     
       6. The benzimidazole composition of  claim 1 , wherein the at least one surfactant is a linear alcohol ethoxylate, ethylene glycol and/or propylene glycol. 
     
     
       7. The benzimidazole composition of  claim 1 , wherein the at least one benzimidazole has a toxicity as measured by LD50 of more than 5,000 mg/kg body weight. 
     
     
       8. The benzimidazole composition of  claim 1 , wherein the at least one benzimidazole has a toxicity as measured by LC50 of more than 100 mg/L. 
     
     
       9. A metal or alloy in contact with the benzimidazole composition of  claim 1 . 
     
     
       10. A steel in contact with the benzimidazole composition of  claim 1 . 
     
     
       11. A method for inhibiting corrosion of a metal or alloy in the presence of water or other corrosive agent comprising contacting the metal or alloy with the composition of  claim 1 . 
     
     
       12. The method of  claim 11 , wherein the metal or alloy is low carbon or mild steel containing up to 0.3% carbon. 
     
     
       13. The method of  claim 11 , wherein the metal or alloy is a medium carbon steel containing 0.3 to 0.6% carbon. 
     
     
       14. The method of  claim 11 , wherein the metal or alloy is a high carbon steel containing more than 0.6% carbon. 
     
     
       15. The method of  claim 11 , wherein the metal or alloy is a stainless steel. 
     
     
       16. The method of  claim 11 , wherein the metal or alloy is contacted with a concentration of 10 to 100 ppm of the benzimidazole composition. 
     
     
       17. The method of  claim 11 , wherein the metal or alloy is part of a system for oil or gas production, transport, or refining. 
     
     
       18. The method of  claim 11 , further comprising incorporating the benzimidazole composition into a petroleum product or a solution containing a petroleum product. 
     
     
       19. The method of  claim 11 , further comprising contacting a system that produces, transports or refines a petroleum product with the benzimidazole composition. 
     
     
       20. The method of  claim 11 , further comprising contacting a system that produces, transports or refines a petroleum product with the benzimidazole composition; wherein said system does not produce waste products comprising a toxic amount or concentration of said composition.